The remedy to Starmer’s “island of strangers” diagnosis, about the only thing he got right, before predictably taking it back, lies not only in renewed policies to promote social cohesion and combat extremism. It also lies in treating these flags, and the impulse behind their prevalence across British high streets, as a force for good. The collective spirit of the Left ought to reclaim and own them. Its opponents, no doubt, raise the issue of Britain being diverse and open. But the national flag is not an obstacle to a multicultural society. It is the precondition for one. A country...